Case 2:
Assuming that above is forbidden and we can only base on "referral-based rewards"
[as in FB example]
can I [as a reward] turn off Ads
if user post message on wall and someone else do action on this post [comment or like ...].

1 Answer
1

It is not allowed as the incentive is directly linked to the user posting a story as stated here which I am also quoting here

While our policies prohibit directly tying incentives to the use of our Social Channels, e.g. rewarding users for the sole act of posting a Stream stories or sending a Request, we do allow for referral-based rewards where our Social Channels are indirectly tied to the potential in-app reward.

So instead of giving incentive directly you may consider making indirect incentive by using either referral or like.

Regarding your case 2, there is very less documentation available on Facebook policy to say correctly about this case where you can turn off adds based on the fact that someone posts to the wall or someone like the post. But I will like to make a few observations that I made:-

Facebook policy says that it doesn't allows use of their social channel directly, i.e you are not allowed to give incentive based on the wall posts, which they have mentioned.

You can give incentive if the user gets more users for your application by referring it.

I have seen a few applications that I use, which use the action link to give certain incentives to the users. One I would like to mention is the EA's SimcitySocial

So for your second case I would suggest not to use posting as a means of giving gift, but instead you should use a further action on it by either linking with action link or URL within message body of post as a means of your incentive.